The Evaporating Universe: Dark Sector Unification via Dissipative Soliton Phase Transitions

The Hubble tension (4.9σ) and cosmological lithium problem remain unexplained within ΛCDM.We propose that Dark Energy and Dark Matter may share a common origin as distinct dynamicalphases of a single dissipative scalar field. In the cosmic background, the field drives late-timeacceleration with a phantom equation of state (w0 = −1.2), while in overdense regions, macroscopicquantum pressure induces condensation into solitonic cores. This phase transition occurs at ztrans ≈0.22, a value derived from first principles rather than fitted. Using only two free cosmologicalparameters (H0, Ωm)—the same as ΛCDM—we obtain H0 = 73.4±3.6 km/s/Mpc (0.1σ vs SH0ES),S8 = 0.774 ± 0.013 (0.2σ vs Weak Lensing), and CMB consistency (∆χ2 = 0.81). The scalar massmϕ = 4.95 MeV enables Be-7 photodisintegration during BBN, addressing the lithium-7 problem.This unified Lagrangian offers a consistent framework spanning cosmological to galactic scales,presenting a potential fundamental alternative to the standard dark sector paradigm.